Motor-control system



A. L. HARVEY.

' MOTOR CONTROL SYSTEM APPLLCATI'ON F-|LED NOV- 7, F911.

Patented Sept. 13,1921.

WITNESSES: INVENTCR ATTORNEY UNITED STATES PATENT OFFICE.

ALBERT L. IIABVEY, OF BRAIDDOCK TOWNSHIP, ALLEGHENY COUNTY, PENNSYL- VANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC & MANUFACTURING COM- PANY, A CORPORATION OF PENNSYLVANIA.

MOTOR-CONTROL SYSTEM.

Specification of Letters Patent.

Patented. se t. 13, 1921.

Application filed November 7,1917. Serial No. 200,661..

To all-whom it may concern:

Be it known that I, ALBERT L. HARVEY, a citizen of the United States, and a resident of Braddock township, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Motor-Control Systems, of which the following is a specification.

My invention relates to systems of control and particularly to systems of control .for governing the operation of fluid systems.

One object of my invention is to provide a system of control of the above-indicated character that shall govern the operation of a plurality of motor-operated'pumps in accordance with operating conditions .of a fluid system.

In fluid systems now in service for use in rolling mills and other industrial properties, it is desirable to have the pressure in the fluid systems maintained substantially constant and, in many cases, it is very desirable to severally and jointly control the operation of a plurality ofmotor-operated pumps in each of the fluidsystems. In some systems, it may only'be necessary to vary the operation of a single motor-open ated pump, Whereas, in other systems, it may be necessary to simultaneously vary the operation of a number'of motor-operated pumps in order to maintain the pressure in the system substantially constant.

In a system constructed in accordance with my invention, a fluid system .is provided with a plurality of motor-operated pumps which may be severally and jointly controlled, either manually or automatically in accordance with the pressure in the fluid system.

In the accompanying drawing, the single figure is a diagrammatic view of a control system constructed in accordance with my invention. 7

Referring to the drawing, afluid system 1 is provided with three or more pumping stations, three only of which, 2, 3 and 4, are

- illustrated, for maintaining pressure in the fluid system. Each of the pumping stations ,is connected to a supply circuitembodying supply conductors 5 and 6 and to two con trol' conductors 7 and 8 which are directly connected to a fluid-controlled device 9 for a'purpose to be set forth hereinafter. The pumping station 2 embodles a pump 10, which is directly connected to the fluidprovided for preparing the pumping station for operation, either automatically in accordance with the pressure in the fluid sysstem or manually, at will. embodies two contact members 22, which are adapted to bridge contact terminals 23 and 25, and 24 and 26 when in the upper or automatic position and to bridge contact terminals 25 and 27, and 26 and 28 when in the lower or manual position. The contact terminals 24 and 23 are respectively connected to the control conductors 7 and 8, and the contact terminals 25 and 26 are respectively connected to the field windings l9 and 20 of thepilot motor 17. A single-pole, doublethrow switch 29 embodies a movable contact member 30,- which is adapted to bridge either the contact terminals 31 and 32 or the contact terminals 32 and 33. The switch 29 The switch .21

is provided for controlling the direction of rotation of the pilot motor 17 when the switch, 21 is set for manual operation.

The fluid-controlled device 9, which is connected to the control wires 7 and 8, is adapted to control the various pumping stations in accordance with the pressure in the fluid system 1. The fluid-operated device 9 embodies a contact arm 34 which is pivoted, intermediate its ends, to a support 35 and is provided with two contact members 36 and 37 which are respectively adapted to engage contact terminals 38 and 39 when the. arm 34 is moved to its extreme positions. plunger 40, which operates within a cylinder 41, is connected to the contact arm 34 near one end thereof, and: a compression adapted to operate the plunger 40 and the 'minal's 37 and 39.

matically governed in accordance with the pressure in the fluid system 1; In positions 6 and c of the controller 43, the pilot motor is respectively connected for operation in a forward and in a reverse direction.

Assuming the. switch 21 of the station 2 to be closed in its upper position, in order to govern the operation of the motor-governed pump 10 in accordance with the pressure in the fluid system. 1, and the switches in'the stations 3 and 4 to be similarly connected if it is desired to operate the pumps associated therewith in accordance with the pressure in the fluid system, the system will be automatically controlled by the pressure in the system 1. If the pressure'in the fluid system 1 is reduced below a predetermined point, the spring 42, acting in opposition to the fluid-pressure in the cylinder 41, will give the contact-arm 34 a movement of rotation such as to connect the contact t'er- Thus, a circuit is completed from the negative supply conductor 6 through the contact terminals 37 and 39, control wire 8, contact terminals 23 and 25 which are bridged by one of the contact members 22-field winding 19 and the armature 18 to the positive sup-ply conductor 5. The pilot motor 17 is operated in a clockwise direction to increase the resistance value of the resistor 16 which is included in circuit with the shunt field winding 13 and thus increase the speed of the motor-driven pump 10. vWhen the pressure in the fluid system is raised to normal, the plunger 40 is operated to break the connection between. the contact terminals 37 and 39. d

When the pressure in the fluid syste-n is raised somewhat above normal pressure, the arm 34 is operated by the plunger 40 to connect the contact terminals 36 and 38 and complete a circuit through the field winding 20 of the pilot, motor '17. through the pilot motor is traced from the negative supply conductor '6, through contact terminals, 36 and 38, control wire 7 contact erminals 24- and 26-which are bridged b one of the contact members 22- field windi g 20 and the armature 18, to the positive s pply conductor 5. The pilot-inotor 17 -is'now1operated in a counter-clockwise direction to' reduce the resistance in- The circuit cluded in circuit with the shunt field winding 13 and thus reduce the speed of the motor-operated pump 10. In setting forth the operation of the pumping station 2, it is to be understood that any of the other pumping stations may be jointly controlled of the switch'29. When it is desired to increase the speed of the motor 10, the switch 29 is closed in its lower position and a circuit is completed from the negative supply conductor 6, through contact terminals 32 and 33which are bridged by the contact member 30-contact terminals 25 and 27- which are bridged by one of the contact members 22field winding 19 and the armature 18, to the positive supply conductor 5. The pilot motor 17 and the contact arm 15 are rotated in a clockwise direction to increase the resistance included in circuit with the shunt field winding 13 and thus operate the motor 11 and the pump 10 at an increased speed.

In case it is desired to reduce the speed of the motor 10, the switch 29 is closed in its upper position andv a circuit is completed from the negative supply conductor 6 through contact terminals 31 and 32 which are bridged by the contact member 30-field winding 20 and the armature 18 to the positive supply conductor 5. The pilot motor 17 and the contact arm 15-are rotated in a counter-clockwise direction to decrease the amount of resistance included in circuit with the shunt field winding 13 v and thus reduce the speed of the motor 11 and the pum 10. i

Although have described my invention in combination with a fluid system, it is to be understood that .the same may be utilized for operating motor-operated gate valves, regulators, fans and any other similar devices.

Modifications in the system and arrangement and location of parts may be made within the spirit and scope of my invention, and such modifications are intended to be covered by the appended claims.

-I claim as my invention:

1. In a system of control for a fluid system, the combination with a plurality of fluid pumps formaintaining pressure in the fluid system, a plurality'of motors severally connected to said pumps, rheostats for governing the excitation of said motors, and pilot motors for respectively controlling the operation of said rheostats, of a supply circuit, and means for jointly connecting any number of said pilot motors to the supply circuit and controlling the operation thereof in accordance with the pressure in the fluid system.

2. In a system of control for a fluid system, the combination with a plurality of pumps and a plurality of motors for maintaining pressure in the fluid system, rheostats associated with the motor field Windings, and pilot motors for respectively controlling the operation of said rheostats, of means for automatically controlling from a distant point the operation of said pilot motors in a forward and in a reverse direction in accordance with the pressure in the fluid system. 1

3. In a fluid control system, the combination with a fluid pressure system, means comprising a plurality of main motors having armatures and field windings for maintaining pressure in the fluid system, a plurality of rheostats, and ilot motors for respectively controlling said rheostats to govern the excitation of said main motors, of automatic means controlled in accordance with the pressure in said fluid system for governing the operation of said pilot motors from a distant point.

4. In a fluid control system, the combination with a fluid system, means comprising a plurality of main motors for maintaining pressure in said fluid system, and a plurality of rheostats and of pilot motors for controlling the energization of said motors, of means controlled by the pressure in said fluid system for simultaneously governing the operation of said pilot motors in a forward and in a reverse direction.

In testimony whereof, I have hereunto subscribed my name this 24th day of Oct.,

ALBERT L. HARVEY. I 

